This invention relates to landing gear for trailers and more particularly relates to the structure of a landing gear sand shoe.
Landing gear for trailers are often subjected to sudden vertical shock forces and to horizontal load forces. A vertical shock force typically occurs when a trailer is uncoupled from a tractor and the forward end of the trailer is dropped to the ground upon its landing gear. Horizontal loads upon the landing gear occur when a tractor pushes against the trailer during coupling. The horizontal coupling forces tend to move the landing gear legs horizontally relative to the sand shoes possibly damaging the shoes or even shearing the shoes from the legs. One solution to this problem is provided by Dalton, U.S. Pat. No. 3,666,290 which teaches a rubber toroid disposed between the base of a round strut and a horizontally disposed foot plate, the toroid being encircled by a skirt congruently fit to the strut to prevent horizontal forces from shearing the toroid.
However, vertically retractable landing gear pose a problem not solved by Dalton. In such landing gear, the legs extend part way to the ground in the retracted condition, and the sand shoes often strike objects over which the trailer passes. It is thus advantageous to have sand shoes whose bottom surfaces are, upon landing gear retraction, tilted upward at the front edge rather than horizontally disposed as taught by Dalton. It has been found that an upwardly tilted sand shoe is less likely to snag upon objects passing beneath the trailer when the trailer is moved forward and that the tilted bottom surface of a landing gear shoe will often deflect objects striking the foot plate from a forward direction.